Fuel consumption of timber harvesting systems in New Zealand

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Fuel is a major cost in timber harvesting operations. Changes in fuel cost are also typically used by forestry
companies in New Zealand to adjust unit harvesting rates. There is however no benchmark on fuel consumption
rates for the different harvesting systems to assist optimizing the design of operations. Seventeen g round-based
and 28 cable logging crews in New Zealand were surveyed on annual fuel consumption, production, stand and
terrain attributes, type and number of machines used and their kW rating. The average rate of fuel consumption
was 3.04 lt/m3 and 0.15 lt/ kWh for ground-based systems, and 3.18 lt/m3 and 0.09 lt/kWh for cable yarder
systems. There was no significant difference between the two groups for the average rates of fuel consumption in
lt/m3, but ground-based system were significantly less energy efficient (more lt/kWh) than cable yarder systems.
The average rate of fuel used per unit volume harvested decreased with total annual system production. Rates of
fuel consumption in lt/kWh are influenced by the type of harvesting system used, total productio n, number of
machines used, average machine power, slope, directions of pulling during extraction and surface moisture
conditions during harvesting. Using standard published machine costing spreadsheets, fuel costs per unit volume
of wood harvested was approximately 15% of the total harvest system cost.